Ib review 1
- 1. Realm of physics SI units – fundamental – kg, s, m, amp, mole, K -derived – Newton composed of kg, s, m - watt, joule, coulomb, volt, ohm Kg2 lb myard N apple Orders of magnitude – powers of ten
- 2. In the study of the motion of fluids we often refer to their “viscosity” (symbol η). The following formula gives a method of measuring viscosity F = 6πηrv F represents a force r represents a distance v represents a velocity This means that the units of viscosity (η) are A. Ns-1m-2 B. Nm-2s C. N-1m2s-1 D. kgm-2s
- 3. Error •systematic - caused by flawed devices, uncalibrated, cannot be reduced by more trials, affects the accuracy Evidence: a graph that should hit the origin is off 2) random - affects the precision, more trials can help this Evidence – points are scattered around the best fit line
- 4. Uncertainties How determined: analog (meterstick, grad cyl)- half the smallest division digital – the smallest scale division Uncertainty in a calculated value = sum of % uncertainties
- 5. Uncertainty in mass is 5%, speed is 10% What is the uncertainty in momentum (p=mv) and kinetic energy (1/2 mv2)? The lengths of the sides of a 5 0 ± 0 ·5 m m rectangular plate are measured, and the diagram shows the 2 5 ± 0 ·5 m m measured values with their uncertainties. Which one of the following would be the best estimate of the percentage uncertainty in the calculated area of the plate? A. ±0·02% B. ±1% C. ±3% D. ±5%
- 6. Vector Scalar Displacement Distance Velocity Speed Acceleration Mass Force Energy Momentum Temp Any field strength Voltage Adding and subtracting – tip to tail Resolving into components
- 7. Which one of the following is not a vector quantity? A. velocity B. work C. weight D. acceleration.
- 8. Masses (kg) Universe 1050 Sun 1030 Earth 1024 Virus 10-21 Hydrogen atom 10-27 Electron 10-30
- 9. Lengths (m) Distance to edge of universe 1026 Distance to nearest star 1016 Diameter of solar system 1013 Distance to sun 1011 Radius of earth 107 Size of hydrogen atom 10-10 Size of nucleus 10-15 Size of proton 10-17
- 10. Time (s) Age of universe 1018 Age of earth 1017 Time of travel by light to nearest star 108 One year 107 One day 105 Period of a heartbeat 1 Period of red light 10-15 Passage of light across a nucleus 10-24